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Darwin Correspondence Project

From James Torbitt   24 February 1878

58 North Street | Belfast

24 Feby. 1878

Ch. Darwin Esqr. | Down Beckenham Kent.

Dear Sir

With best thanks for your kind letter of 30th. July last,1 I beg leave to enclose letter to the Chancellor of the Exchequer, which explains the progress I have made in the cultivation of the potato, notably as cross-fertilized. In it, I have availed myself, to the extent of twenty copies, forwarded to the Chancellor, of your most kind permission to “use your letters for the purpose of persuading persons to grow the plant from the seed” But always asking favours, I would ask now may I be permitted to use them for the purpose of persuading the public to do so, that is, may I be permitted to send, as it stands, a copy of enclosed letter to the press?2

If you can kindly admit of it, I shall have some hope of obtaining assistance, if not, this year will be lost because I cannot afford to expend more money in that direction at present.

I have the pleasure to forward some specimens of the cross-fertilized varieties, and am, believe me Dear Sir, with best wishes, and profound respect, | very faithfully yours | James Torbitt


58, North Street, Belfast,

23rd February, 1878.

To the Right Hon. Sir Stafford H. Northcote, Bart., C.B., Chancellor of the Exchequer, &c., London.

Right Hon. Sir

(Cultivation of the Potato.)

It is with great reluctance that I trespass on the attention of the Government at present, but spring is coming on, and if this season is not to be lost, I must wait no longer.

The matter is this: For the last three years I have been engaged in the endeavour to obtain from the seed of the potato varieties which should present a greater than usual resistance to the attack of the parasite, whose growth in the body of the plant constitutes the disease. Of these varieties I now beg leave respectfully to submit I have found several; and, in addition, I have discovered a fact probably of far wider importance: I have ascertained that the young varieties are much more vigorous and prolific than the old.

My experiments and their results are as follow:

In the season 1875, I grew 5,000 plants of the potato from the seed of the flower, and in the autumn I dug them up one by one. By far the greater number were greatly diseased or otherwise worthless, and these I destroyed. The remaining plants produced each a few tubers, constituting what is called a variety. These I placed in paper bags, each by itself, and during the winter many more of them became diseased, and I destroyed them.3

In the spring of 1876, I planted out the varieties in the paper bags, each by itself, and in the autumn found that a further number had become more or less diseased, and these also I destroyed. The remaining varieties I preserved on trays, and during the winter, a farther number became diseased, and I destroyed them.

In the spring of 1877, I again planted separately the surviving varieties, and in the autumn found a further number greatly diseased, and destroyed them. During the winter a further number of varieties became badly diseased, and were destroyed, leaving now (19th February, 1878), out of the original 5,000 seedlings of 1875, some thirty varieties so slightly diseased as to be practically disease-proof, not more than from one tuber in ten to one in forty being affected, and these are of excellent qualities, and of immense yield, say from ten to twenty tons per acre. Note—At the beginning of the present century, T. A. Knight, Esq., of Downton Castle, found thirty-four tons, “and there is no more trustworthy authority.”4

Besides these I have three 1875 varieties which have been absolutely disease-proof in every tuber during their three years of life, although, like all the others, growing in the presence of infection, and for the most part in contact with the foliage of diseased plants.

And these results have been obtained from the common self-fertilized flowers of the plant.

But Mr. Darwin has ascertained that cross-fertilization of plants gives to them an increased vigour of life to the enormous extent of one-third to one-fourth,5 and by his revered recommendation I crossed two of the most powerful seedlings I had (summer 1876), and in the spring of 1877 I planted out 2,000 plants obtained from these seeds, the result being in the autumn some two hundred absolutely sound varieties, and some hundreds more almost free of the pest and almost all beautiful in appearance.

As to the question of the probability of a continuance of their comparative immunity from disease for some years forward, Mr. Darwin, writing on the 14th April, 1876, does me the high honour to say that “the more I reflect on your scheme the more I believe it is the one plan for succeeding in getting a sound variety;” and again on 30th July, 1877, he permits me to say “that my plan—namely, the preservation during successive generations of those seedling plants, all the tubers of which are sound, and the destruction of all other plants, in conjunction with cross-fertilization—is in his opinion by far the most likely method by which to obtain a sound variety;” and that “I have his best wishes that I may have the satisfaction of conferring a great benefit on the world.”6

Under these circumstances, I now beg leave respectfully to place at the disposal of the Government the above described sound—comparatively sound—and exceedingly prolific varieties of the plant, and should the offer obtain the honour of acceptance (three or four acres will suffice to contain them for this season) I shall at once forward them to the address indicated, or, if desirable, take charge of them here.

As to what they cost, and should anything be paid for them? These questions can, if deemed proper, be taken into consideration hereafter—after it shall have been ascertained whether or not they are of any value.

Some days ago I had the honour, right hon. sir, to send to your address at Whitehall, one basket of specimens, and I now respectfully beg leave to describe them. One bag in the basket contains twenty-six tubers of 1875 seedlings, being of varieties almost absolutely disease-proof. Another bag contains the whole of a variety grown from a seed, sown in the spring of 1876, and showing the powers of reproduction of the plant. The ten or twelve paper-bags each contain a cross-fertilized variety, grown from a seed sown in the spring of 1877.

Should the few hundred varieties offered above be accepted of, and turn out practically disease-proof, and of large yield, as I believe they will; still it will be many years before they can become of sufficient bulk or quantity to be of any commercial value, and in the meantime the disease will continue its ravages.

With great respect then, I submit that the best method by which to combat the evil would be to grow the plant this spring from the seed in hundreds of thousands, or, if need be, in millions, and to distribute the resulting varieties, which may be valuable, to the farmers all over the kingdom. The effect would be a largely increased supply of cattle food in the autumn of 1879, and, I think, a commencement of the suppression of the disease in 1880.

Finally, right hon. sir, I hold in my hand several hundreds of thousands of the cross-fertilized seeds, and some fifty millions of the common self-fertilized—each the representative of a new variety—and I am prepared, if assisted, to undertake the re-introduction of the plant to these kingdoms. Should I fail, it would involve the loss of a few thousands in the prosecution of an experiment the principle of which is approved of by the highest authority of the world; should I succeed, the success would be of world-wide significance, as the principle applies to the vine as well as to the potato, to the phylloxera as well as to the peronospora,7 and, as I suspect, to all plants propagated by their buds. And if Government does not consider this project within its proper sphere of action, I would ask permission to publish this letter and the reply, in the hope of attracting the attention of some of the great interests affected.

I beg leave to subscribe myself, right hon. sir, | Very respectfully and faithfully | Your obedient servant, | James Torbitt.


In 1876, CD had objected to Torbitt’s use of his letters in advertisements; see Correspondence vol. 24, letter to James Torbitt, 21 April 1876. For more on CD’s long-standing interest in potato blight, see Ristaino and Pfister 2016.
For details of Torbitt’s experiments up to 1875 to cultivate blight-resistant potatoes, see Torbitt 1876.
Thomas Andrew Knight claimed this yield in Knight 1833, p. 417; see also Torbitt 1876, p. 22.
For CD’s discussion of the greater constitutional vigour of crossed plants, see Cross and self fertilisation, pp. 285–91.
The first two quotations are from the letters to James Torbitt, 14 April 1876 (Correspondence vol. 24) and 30 July 1877 (Correspondence vol. 25). The third is not an exact quotation from any known letter.
Phylloxera (Daktulosphaira vitifoliae) is a small sap-sucking insect native to North America, accidentally introduced in the mid nineteenth century to Europe, where it devastated native grapevines because it attacked the roots. In American vines, the insect usually only affected the leaves. Peronospora infestans (a synonym of Phytophthora infestans) is a species of oomycete or water mould parasitic on the potato.


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Cross and self fertilisation: The effects of cross and self fertilisation in the vegetable kingdom. By Charles Darwin. London: John Murray. 1876.

Torbitt, James. 1876. Cras credemus. A treatise on the cultivation of the potato from the seed, having for proposed results the extinction of the disease, and a yield of thirty, forty or more tons of tubers per statute acre. (Sent, accompanied by a packet of seed, to each member of the House of Lords; each member of the House of Commons; and the principal landlords of Ulster.) Belfast: printed by Alexander Mayne.


Wants CD to forward to Chancellor of Exchequer a letter which explains the progress he has made in his potato crossing. Wants to print a CD letter to arouse public interest in the work.

Letter details

Letter no.
James Torbitt
Charles Robert Darwin
Sent from
Source of text
DAR 52: E2, DAR 178: 137
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 11373,” accessed on 14 May 2021,